The answer to 'roof decking water stains' is that they are a common issue caused by leaks or moisture intrusion. Water stains on the roof decking, which is the structural material beneath the roof, can indicate a problem that needs to be addressed. Symptoms may include visible discoloration, warping, or even mold growth on the decking.
The most common causes are roof leaks, poor ventilation, or inadequate insulation allowing condensation to form. Resolving the issue often requires identifying and repairing the source of the moisture, which may involve fixing flashing, replacing damaged shingles, or improving attic airflow. In some cases, the decking itself may need to be replaced if it has sustained significant damage.